Halogen filament lamp

ABSTRACT

A method of manufacturing a halogen filament lamp in which a wire supporting the filament of the lamp is used having a meltable metal portion. The meltable metal portion is oriented approximately opposite to the sealing foil and the metal portion melts away during the formation of the pinch seal. The method provided a capability of permanently supporting the filament even during the pinching operation.

United States Patent 1191 [111 3,743,375 De Fraeye July 3, 1973 HALOGENFILAMENT LAMP [56] References Cited [75] Inventor: Dirk Jules Reml DeFraeye, UNITED STATES PATENTS Emmasmgel, Emdhoven 3,408,719 11/1968 VanSickler et al 29/2s.1s Netherlands 3,600,053 8/1971 Smith 316/19 73Assignee: U.S. Philips Corporation, New York,

N,Y, Primary ExaminerCharles W. Lanham Assistant Examiner-J. W. Davie[22] 1971 Attorney-Frank R. Trifari [21] Appl. No.1 126,552

- [57] ABSTRACT [30] Foreign Application Priority Data 1 A method ofmanufacturing a halogen filament lamp in Apr. 4, 1970 Netherlands7004872 hi h a wire su orting the filament of the lamp is used having ameltable metal portion. The meltable metal Cl 9/25.l5, 313/235, portionis oriented approximately opposite to the seal- 313/315 ing foil and themetal portion melts away during the [5 l 1 Int. Cl. H01] 9/38 formationof the pinch seal, The method provided 3 C8- [58] Field of Search316/18, 19, 20;

pability of permanently supporting the filament even during the pinchingoperation.

5 Claims, 5 Drawing Figures PATENTEUJIIL 3 1975 Fig.5

INVEN'IOR. DIRK J.R. DE FRAEYE AGENT HALOGEN FILAMENT LAMP The inventionrelates to a method of manufacturing a tubular halogen filament lampwhich comprises a tubular lamp vessel closed by at least one pinch seal,in the longitudinal direction of which vessel is arranged a filamentwhich is connected to at least one lead-in member incorporated in thepinch seal, said filament being supported in at least one place by apart of a supporting wire likewise extending in the longitudinaldirection of the lamp and embedded in the pinch seal. Such a method isknown from German Utility Model 6,753,344.

The parallel arrangement inside a tubular lamp vessel of an elongatedfilament and a wire supporting the filament is rather difficultconsidering that the supporting wire must have a shorter length thansuch a filament which is also provided with connecting foils and lead-inconductors. Actually, it is undesirable to lead the supporting wiredirectly through the pinch seal to the exterior; such a lamp has nogas-tight pinch seal. In the manufacture of such lamps, it is thereforealways difficult to cause the supporting wire to assume the pre scribedposition relative to the filament during the pinching operation. On thecontrary, the filament itself will often serve as a support of thesupporting wire during the pinching operation.

It is the object of the invention to provide a method which orients thesupporting wire during the formation of the pinch seal in a preciseprescribed position relative to the filament.

The method according to the invention is characteri zed in that thestarting material is an assembly formed by the filament having securedthereto lead-in members and a wire supporting said filament in at leastone place, a part of said wire being formed by a metal member which ismeltable only during the pinching operation, said assembly beingsurrounded by a glass tubular member, the pinch seal being formed insaid tubular member while embedding the lead-in members and the meltablemetal members, the resulting lamp vessel being then provided with asuitable gas filling and being sealed. By the introduction of a fewmetal members which are not meltable until during the pinchingoperation, it becomes possible to have a supporting wire which, unlikein the known method, is not shorter but longer than the length of thefilament having the lead-in conductors secured thereto. This enables thepositioningof the supporting wire together with the lead-in conductorconnected to the filament so that the position of the supporting wire isfixed upto substantially the instant at which the appropriate squeezingmembers have completed their pinching operation to form the pinch sealin the lamp vessel. Only at that instant does the interposed metalmember melt away. It has been found that the desirable position of thesupporting wire assumed just prior to the sealing and pinching operationis not influenced substantially. In the finished product, this meltedmember remains an electrically insulated metal mass embedded in thepinch seal.

Preferably a meltable metal member is used which is in the form of atube in the two ends of which spaced parts of the supporting wire aresecured. It has been found that this construction in which the tube ispreferably manufactured from nickel, is to be preferred over a solid rodas a metal member.

The invention is particularly suitable for use in a method ofmanufacturing a tubular halogen filament lamp which comprises a tubularlamp vessel sealed at either end by a pinch seal, in the longitudinaldirection of which a filament is arranged which is connected to foilsembedded in the pinch seals, which foils are each connected to a lead-inconductor emerging from the lamp, said filament being supported in atleast one place by a supporting wire likewise extending in thelongitudinal direction of the lamp, said wire being likewise embedded ateither end in the two pinch seals.

This method is characterized in that the starting material consists oftwo parallel chains, one of which is formed by the filament having foilsconnected thereto, to which foils are connected lead-in conductors, andthe other is formed by a wire supporting the filament in at least oneplace and a part of which, which is present approximately at the heightof each foil, is formed by a metal member which is not meltable untilduring the pinching operation, said two chains being surrounded by atubular glass member which is shorter than the length of each chain,pinch seals being formed at either end of said tubular member whileembedding the foils and the meltable metal members, the resulting lampvessel then being evacuated through a lateral exhaust tube, providedwith a suitable gas filling, after which said exhaust tube is sealed. Sofor the manufacture of the lamp two parallel chains are used which canbe held collectively in a particularly simple manner during the pinchingoperation.

According to a preferred embodiment of this method, the two chains maybe united by bridge members to form a single coherent assembly. Theresulting chain may then be closed entirely by using two bridge members.By using such a coherent chain, the handling during the pinchingoperation becomes particularly simple. In that case it is sufficient forthe composite chain to be held by its two bridge members, the chainmaintaining its coherence substantially up to the instant at which thesqueezing members have completed their action. If desirable after theformation of the pinch seal, a separation operation may be carried outon the bridge member formed outside the pinch seal, which bridge memberis secured in said pinch seal at either end. In that case the bridgemember serves as a lead in conductor which is secured to the filamentmember via a sealing foil.

In order that the invention may be readily carried into effect, it willnow be described in greater detail, by way of example, with reference tothe accompanying drawing, in which FIG. 1 shows a two-pinch halogenfilament lamp to be manufactured.

FIG. 2 relates to a method according to the invention,

FIG. 3 shows on an enlarged scale a part of the supporting wire shown inFIG. 2,

FIG. 4 shows a filament lamp obtained by the method according to theinvention, and

FIG. 5 shows a mono-pinch halogen filament lamp.

FIG. 1 shows an electric filament lamp which comprises a tubular lampvessel 1 of quartz glass. At its end said lamp vessel comprisespinchseals 3 and 5. A coiled coil filament 7 of tungsten wire is arrangedinside the lamp. The ends of the filament 7 are secured to sealing foils9 and ll of molybdenum. External conductors l3 and 15 are secured tosaid foils.

The filament 7 is supported in known manner by a loop 17 formed in asupporting wire 19 of molybdenum and extending parallel to the filament7, and the ends of which are embedded in the pinch seals 3 and 5. Thefilament lamp shown is provided with a suitable halogen-containing gasfilling in a manner conventionally used for halogen filament lamps.

According to the invention, starting material for the manufacture of afilament lamp shown in FIG. 1 is an assembly as shown in FIG. 2. Thisassembly comprises the components already described with reference toFIG. 1, which are arranged as two parallel chains inside a tubularmember 23 of quartz glass which is open at either end, in the manner asshown in FIG. 2. In FIG. 2, said tubular member is shown in brokenlines. The first chain comprises the filament 7, foils 9 and 11, andexternal conductors 13 and 15. The second chain is constituted by thesupporting wire 19, metal member 25 and 27 secured thereto, andsupporting wires 29 and 31 which are secured thereto and have the samethickness as the wire 19 and likewise consist of molybdenum. The metalmembers 25 and 27 are chosen to consist of such a material that theymelt only when the operation of the squeezing members to form the pinchseals 3 and is carried out. These members are manufactured, for example,from nickel and are in the form of tubes. FIG. 3 shows the tube 27 on anenlarged scale. The ends of supporting wires 19 and 31 are secured insaid tube 27.

During the pinching operation which is performed subsequently to formthe pinch seals 3 and 5, the assembly comprising the two chains are heldby suitably constructed holders 33 and 35 shown in broken lines. Inthese holders the conductors l3 and 15 and the supporting wires 29 and31 are held in a prescribed position. The loop-shaped part 17 of thesupporting wire 19 can continue to support the filament 7 during theperformance of the pinching operations.

During the formation of the pinch seals 3 and 5, the ends of the tubularmember 23 which are softened by heating are squeezed between twosqueezing blocks not to be described in detail. Just before the quartzglass contacts the members 25 and 27, the members 25 and 27 will meltduring which time the position of the supporting wire 19 does not varyto any substantial degree. This lamp vessel is then evacuated, providedwith a suitable gas filling, and the exhaust tube 21 is sealed.

The resulting product is shown in FIG. 4. In this Figure the meltedmetal members 25 and 27 form insulated embedded masses 37 and 39,respectively. Viewed from the supporting wire 19, they are embedded inthe elongation of the ends of the wire in the pinch seals 3 and 5 in anelectrically insulted manner between the wire parts 19 and 29 and 19 and31, respectively.

In the above embodiments, the starting material was constituted by twoseparate parallel chains. It will be obvious that it is also possible touse a single closed chain having two parallel branches connected bybridge members 41 and 43 as they are shown in broken lines in FIG. 4.Such a closed chain has the advantage of forming a rigid coheringassembly up to the formation of the pinch seals. In that case, the extrabridge members 41 and 43 may be formed by bending back the parts 29 and31 of the supporting wires and connecting them to the foils 9 and 11.The parts of the wire present outside the pinch seals 3 and 5 are theneach incorporated with their two ends in the pinch seals in an insulatedmanner and may serve as external connection members. If desirable, aseparation operation may be carried out along the broken lines 45 and47.

The invention has been described with reference to an embodiment for afilament lamp having two pinch seals. Of course it is equally suitablefor use in a filament lamp having only one pinch seal (see FIG. 5). Thelamp shown in FIG. 5 also shows a filament 51 which is supported bymeans of a central supporting member 53. This central supporting memberin this case also has a meltable part which melts away only during theformation of the pinch seal. FIG. 5 illustrates the resultant pinchafter the melting has occurred. Again the presence of an embedded mass55 is to be noted.

What is claimed is:

l. A method of manufacturing a tubular halogen filament lamp of the typehaving a tubular lamp vessel sealed by at least one pinch seal, saidvessel having a longitudinal filament connected to at least one lead-inmember which is incorporated in the pinch seal, the filament beingsupported in at least one place by a supporting wire which wire isembedded in the pinch seal and extending longitudinally in the lampcomprising the steps of:

arranging as an assembly an elongated filament having at least onelead-in member attached thereto and a supporting wire, said supportingwire positioned to be substantially parallel to the longitudinal axis ofthe tube and supporting the filament in at least one place, said wirehaving a portion including a member meltable during the pinchingoperation;

surrounding said assembly by an elongated glass tubular member;

pinching at least one end of said member by applying pressure and heatso as to simultaneously melt said wire member and form a pinch seal forsaid lamp; evacuating said lamp;

filling said lamp with an appropriate gas atmosphere;

and sealing said lamp. 2. A method of manufacturing a tubular halogenfilament lamp of the type which is sealed at either end by a pinch sealand has a longitudinal filament connected to foils embedded in the pinchseal, which foils are each connected to a lead-in conductor whichemerges from the lamp, the filament being supported in at least oneplace by a part of a supporting wire which similarly extendslongitudinally within said lamp, said wire also being embedded at eitherend, said method comprising the steps of:

coupling a first chain of elements including a filament, foils securedto either end of said filament, and lead-in conductors secured to saidfoils;

coupling a second chain of elements and orienting it substantiallyparallel to said first chain, said second chain including a wiresupporting said filament in at least one place and a pair of meltablemetal members positioned approximately opposite said foils; surroundingsaid two chains by a tubular glass memher which is shorter than thelength of each chain;

forming pinch seals at either end of said tubular member, therebyembedding the foils and melting and embedding the meltable members insaid pinch seals;

evacuating said resulting lamp vessels through a lateral exhaust tube;

5. A method as claimed in claim 2, wherein the starting material is asupporting wire of which at least one of the ends is bent back andsecured to one of the foils,

in which after the formation of the pinch seal a separation operationmay be carried out on the bent'part of the supporting wire extendingfrom the lamp vessel.

2. A method of manufacturing a tubular halogen filament lamp of the typewhich is sealed at either end by a pinch seal and has a longitudinalfilament connected to foils embedded in the pinch seal, which foils areeach connected to a lead-in conductor which emerges from the lamp, thefilament being supported in at least one place by a part of a supportingwire which similarly extends longitudinally within said lamp, said wirealso being embedded at either end, said method comprising the steps of:coupling a first chain of elements including a filament, foils securedto either end of said filament, and lead-in conductors secured to saidfoils; coupling a second chain of elements and orienting itsubstantially parallel to said first chain, said second chain includinga wire supporting said filament in at least one place and a pair ofmeltable metal members positioned approximately opposite said foils;surrounding said two chains by a tubular glass member which is shorterthan the length of each chain; forming pinch seals at either end of saidtubular member, thereby embedding the foils and melting and embeddingthe meltable members in said pinch seals; evacuating said resulting lampvessels through a lateral exhaust tube; filling said lamp with anappropriate gas; and sealing said lamp.
 3. A method as claimed in claim1, wherein the meltable metal member is in the form of a tube in the twoends of which parts of the supporting wire are secured at some distancefrom each other.
 4. A method as claimed in claim 3, wherein the metalmember is in the form of a nickel tube.
 5. A method as claimed in claim2, wherein the starting material is a supporting wire of which at leastone of the ends is bent back and secured to one of the foils, in whichafter the formation of the pinch seal a separation operation may becarried out on the bent part of the supporting wire extending from thelamp vessel.